1. Field of the Invention
This invention relates to a generator in a wheel of a bicycle with collective multiple poles.
2. Description of the Prior Art
A conventional generator, especially applied to a wheel hub of a bicycle, is generally a nail-type magnetic-pole generator including a cylindrical member made of permanent magnet for which a wheel hub shell is used, and two stator yokes consisting of a disc and multiple nail-shaped poles extending from the disc in an annular form and facing to the permanent magnet. Further, an iron core is fixed on a hub shaft inside the cylindrical member for forming magnetic circuits to let magnetic line of force the stator yokes to pass through. A plate-shaped coil wound on a coil frame is provided around the iron core, so the hub shell and the cylindrical member (or the permanent magnet) constitute a rotor, and the two stator yokes, the iron core, the coil frame, the coil and the hub shaft constitute a stator. When the rotor of the hub shell is rotated by the spokes of the front or the rear wheel, the magnetic lines of force of the permanent magnet may be transmitted from the finger-shaped poles to the nail-shaped magnetic poles of the other stator yoke via the iron core, and alternate magnetic lines of force of different directions may be produced on the iron core, so the coils on the coil frame may produce electric current, which is to be supplied to electronic appliances on the bicycle.
However, the conventional generator with finger-shaped poles has the plate-shaped coil, which must be made manually, impossible to be made by mechanical process, so it is made very slowly, resulting in a high cost. In addition, magnetic wire volume required by the coil is also quite large, heightening its material cost. Besides, the electric power generated by the conventional generator may be not enough for electronic appliances on the bicycle.